open the dll in a hex editor,
remember the byte at entry point and patch it to 0xCC,
make sure your softice/ollydbg/whatever is configured to break on int3,
start the program in the debugger,
wait for int3 break in dll,
patch back the byte you remembered,
set eip back to the entry point to execute this original code (with byte patched pack),
now do whatever is needed to unpack it, trace etc
